This proposal requests funds for the Whitehead institute for Biomedical Research (WI) to purchase a sensitive, automated protein sequenator which would be available to investigators at WI, as well as the M.I.T. Center for Cancer Research and the Department of Biology. The sequenator would be part of WI's Protein Analysis and Synthesis Laboratory, which already serves the WI-MIT biology community. WI is committed to its long term operation and maintenance and would provide funds to hire a technical person to supervise the operation of a sequenator and to provide technical expertise to the users. A protein sequenator would be essential tool in many PHS-supported research projects going on here, such as our studies on the structure and function of the intestine brush border, studies on the regulation of histidine biosynthesis in yeast, studies on the molecular biology of poliovirus, a genetic and biochemical analysis of yeast RNA polymerase, and our research on the interactions of oncogenes with developing systems.